feat(api): add delete speaker functionality and corresponding tests

- Implemented a DELETE endpoint for removing speakers, including necessary authorization checks and response handling.
- Added a handler for the delete operation in the HTTP API.
- Created unit tests to verify the delete functionality, ensuring proper deletion and response codes.
- Updated OpenAPI documentation to reflect the new delete speaker endpoint.

internal/repository/postgres.go

@@ -646,6 +646,18 @@ func (p *Postgres) UpdateSpeaker(tenantID, id string, patch *store.SpeakerPatch)
 	return p.GetSpeaker(tenantID, id)
 }
 
+func (p *Postgres) DeleteSpeaker(tenantID, id string) error {
+	ctx := context.Background()
+	tag, err := p.pool.Exec(ctx, `DELETE FROM bgp_speaker WHERE id=$1 AND tenant_id=$2`, id, tenantID)
+	if err != nil {
+		return err
+	}
+	if tag.RowsAffected() == 0 {
+		return store.ErrNotFound
+	}
+	return nil
+}
+
 func (p *Postgres) GetRevision(tenantID, revisionID string) (*store.Revision, error) {
 	ctx := context.Background()
 	var r store.Revision